1. Field of the Invention
The present invention relates to a production process for a self-dispersible pigment, a self-dispersible pigment, an ink, an ink cartridge and an ink jet recording method.
2. Description of the Related Art
A self-dispersible pigment is mainly produced by a chemical pigment-modifying technology. For example, Japanese Patent Application Laid-Open No. H10-510861 describes a process for obtaining a self-dispersible pigment by causing a pigment to react with a diazonium salt. In addition, Japanese Patent Application Laid-Open No. H08-003498 describes a process for obtaining a self-dispersible pigment by causing a pigment to react with hypohalous acid.
However, the conventional pigment-modifying technologies have not satisfied a production process with high safety and reaction efficiency taking environmental burdens which have been regarded as important in recent years into consideration. In, for example, the production process described in Japanese Patent Application Laid-Open No. H10-510861, a nitrite low in stability is utilized. In addition, residue of the nitrite or a nitrogen oxide may occur in some cases in the process of treating a pigment with a diazonium salt. Further, reaction efficiency is hard to be improved due to bubbles generated in the reaction. Even in the production process described in Japanese Patent Application Laid-Open No. H08-003498 on the other hand, the reaction efficiency is low, and the resultant pigment is also hard to be purified because impurities are produced in plenty.